ON/OFF signals - Buttons and lamps

Buttons and signal lamps are using simple digital inputs and outputs i.e. ON/OFF signals. Digital inputs and outputs signals are most basic and also most common signal types on PLC controllers. With input signals controller can acquire information from sensors or human operators. For example contact sensors or contactless proximity sensors inform controller that some object is touched or is apparent in range. Based on this data PLC can generate output signal to stop the motor, light up the signal lamp etc. Simple buttons act as digital inputs and enables to provide human interaction to machine.